8.1 Introduction

(b) advice about satisfying assessment benchmarks in the planning scheme.

(2) This chapter applies to design and construction of the following:

(a) bridges;

(b) culverts;

(c) tunnels;

(d) earth retaining structures;

(e) elevated structures;

(f) water access structures;

(g) sea- and river wall structures;

(h) fences.

(3) The purpose of this chapter is to ensure consistent, best value, whole-of-life design outcomes for these structures and assets, and to achieve the following outcomes:

(a) the entire completed structure is safe, flood resistant, aesthetically pleasing, functional and easy to maintain without the need for specialised techniques, plant, skills or equipment not readily available in South East Queensland;

(b) the structures are designed and detailed to ensure maintenance costs do not exceed on average 1% of asset value per annum including operational maintenance, and maintenance can be carried out without significant noise, disruption or nuisance to users or adjoining property owners;

(c) all structures have an attractive appearance appropriate to their general surroundings and any adjacent structures;

(d) retaining walls and wing walls use simple, straight or large radius curved alignments sympathetic to the road alignment and interfaces with adjoining development, pathways, structures and environmental features;

8.2.3 Design life

(1) All bridges and associated elements are designed to achieve the minimum design life in Table 8.2.3.A without major maintenance or replacement of elements, whilst remaining safe and functional.

(2) If part of an asset including asset items and asset sub-items is not readily accessible for maintenance or replacement, it satisfies the design life requirements of the asset which it forms a part.

(3) A replacement methodology is specified for components that have life shorter than the structure design life.

Table 8.2.3.A— Minimum required design life

Asset

Design life

Bridge structures and roadway support structures including underpasses

8.2.4.3 Concrete durability

(2) Cover spacers or permanent fixings are incorporated within the concrete covers zone and are structurally adequate, durable and compatible with the material characteristics of the surrounding concrete with good adhesion, so that their inclusion will not cause any cracking, spalling or other defect leading to corrosion of the reinforcement within the structures design life.

(7) Coating systems are applied in compliance with the manufacturer’s specifications.

8.2.4.6 Timber durability

(1) Timber girders are not used for a bridge.

(2) Timber decking is not used for a bridge.

8.2.4.7 Miscellaneous components durability

(1) Structures are designed to enable items such as bearings, expansion joint seals, railings and drains to be readily accessible for inspection, maintenance, renewal or replacement.

(2) Structures are designed so that all corrosion protection systems including concrete covers can be easily inspected, maintained or renewed.

8.2.5 Widening

(1) If future widening of a bridge may be required, allowance is made in design for connection of the future widening and wherever possible, the connection is designed and constructed to minimise or eliminate the need to alter the parent structure.

(2) A structure does not include exposed reinforcement or fixings that project from the structure in anticipation of a future widening.

(3) The widening of any existing structures provides a structural solution that is consistent with the existing structure in terms of stiffness, fixity, continuity and appearance.

(4) The effects of the widening on the capacity of the existing structure are considered and the existing structure strengthened as required to ensure no reduction in vehicle capacity.

(5) Articulation of any widened bridge is consistent with existing bridge articulation.

8.2.6 Minimum clearances

Minimum vertical clearances for bridges are complaint with Table 8.2.6.A.

8.2.9 Deck drainage

(2) Drainage from overbridges is not discharged into watercourses, onto railway lines, traffic lanes or shared use paths or footpaths below the bridge.

(3) Drainage pipes are fire resistant and meet the durability requirements of this performance specification. The minimum diameter of scuppers is 150mm and the minimum diameter of drainage pipe is 200mm.

(4) Parapets have a top surface that angle towards the road by a minimum of 2.5° to channel rainwater onto the bridge to minimise staining of the outside parapet face. To conceal any drainage or service pipes, the parapet must hang below the underside of the bridge deck slabs and girder flanges if applicable by a minimum of 100mm.

(2) The condition of existing bearings, and their impact on the performance of a widened bridge, are considered and addressed.

(3) Bearings for new girder bridges are designed and constructed for ease of replacement during the life of the bridge. 'Ease of replacement' is considered as placing a jack on the bearing shelf and jacking against the girder or diaphragm, using normal height commercially hired jacks.

(3) For bridges over Queensland Rail infrastructure/land, special performance level barriers are provided with protection screens.

(4) Where a bridge structure is over permanent water deeper than 300mm or where the drop height exceeds 1.2m, vertical balustrade pedestrian handrails with appropriate bicycle offset rail or equivalent are provided on the structure’s outer edge.

(5) Proposals do not include slip forming of concrete bridge barriers, or use of timber bridge barriers.

8.2.11.2 Pedestrian or bikeway barriers

Where pedestrian or bikeway barriers are liable to inundation they are:

(a) durable, robust, tamper proof and capable of surviving up to a 20 year ARI flood without damage and with minimal maintenance throughout their 40-year design life;

(c) designed so that in the event of failure above a 20 year ARI flood, there will be no damage to the supporting structure or base fixings to enable quick and easy repair or replacement with minimal disruption or nuisance to the public.

8.2.11.3 Collapsible barriers

(1) Collapsible barriers or railings incorporating replaceable weak links (e.g. shear pins), will only be considered when tamper proof and a whole-of-life cost–benefit analysis shows that it is a better value solution than a normal installation.

(2) Collapsible barriers or railings of any type are not to be relied upon to mitigate flood impacts to adjoining land or infrastructure.

8.2.11.4 Noise barriers and electrification barriers

(1) Where it is required that noise barriers and electrification barriers be carried across the bridge, the noise barrier panels and posts and electrification barriers are located on the outside of the bridge behind the top horizontal face of the concrete parapet.

(2) The barriers, including support systems, are designed to avoid potential spearing hazards in the event of a collision.

8.2.12 Public utilities

(1) A bridge is designed to accommodate present and future requirements for services crossing the structure.

(2) A road bridge incorporates provision for a minimum of 8 conduits 100mm in diameter as follows:

(a) 3 x 100 diameter – white for telecommunications;

(b) 2 x 100 diameter – orange for electricity;

(c) 1 x 100 diameter – yellow or black with yellow stripes for gas;

(d) 2 x 100 diameter – white spares.

8.2.13 Hydrology

(1) Design for hydrology of road embankment stability is based on a 100 year ARI flood.

(2) Design for hydrology for the ultimate limit state of bridges, major drainage structures and retaining walls stability is based on a 2000 year ARI flood.

(3) The hydraulic loads on bridges are based on a 2000 year ARI flood for ultimate limit state flood levels and flows and a 20 year ARI flood for serviceability limit state flood levels and flows.

(4) The impact of climate change during the structure’s life is assessed and taken into account in assessing flood levels and velocities.

(5) Structures are designed to prevent or minimise increased flooding or flood pattern changes.

8.2.14 Crossfall on bridges

(1) The minimum cross fall on new bridges is 2.5%.

(2) Widened bridge decks have a crossfall similar to the existing bridge deck, and the minimum cross fall is 2.5%.

(3) The existing deck wearing surface on all bridges subject to widening, including bridge approaches where required, is milled to a sufficient depth to allow placement of new asphaltic concrete wearing surface.

(4) Milling does not damage the concrete deck or waterproof membrane if present.

(5) The thickness of the deck wearing surface is minimised so as not to affect the existing load rating.

(6) For existing bridges having a one-way crossfall of less than 2%, the deck wearing surface can be increased in thickness to result in a crossfall of 2% provided the load rating is not adversely affected.

8.2.15 Bituminous waterproof membrane

A bituminous waterproofing membrane is provided for:

(a) all pre-stressed concrete deck unit bridges;

(b) the entire deck of bridges with pre-cast girders and a composite reinforced concrete decks;

(c) the negative moment zone for continuous bridges.

8.2.16 Deck wearing surface

(1) On road bridges:

(a) the deck wearing surface is asphaltic concrete dense grade asphalt and has a design life of 20 years;

(b) the minimum thickness of deck wearing surface on bridges is 60mm in any traffic lane;

8.2.17 Post-tensioned concrete superstructure

(1) Superstructures do not use external pre-stressing.

(2) Where match cast joints in post-tensioned concrete are used, all match cast joints are epoxy coated, waterproofed and have a minimum compressive stress of 2MPa under all serviceability limit state load combinations.

8.2.18 Super-tee bridge girders – skew and stepped joints

(1) Concrete trough and 'Super Tee' girders are not used on structures, which have a skew exceeding 35° to either of the abutments or any of the piers.

8.2.21 Abutments

(1) Where practical, abutments of road overbridges spill through type with a 750mm wide shelf at the top to allow easy inspection of bearings and shelf. The preferred batter slope is 1V:1.5H.

(2) The scour potential at abutments and piers is minimised. The design takes into account this scour and the design life for abutment protection in streams subject to scour is 100 years.

(3) Abutment slope protection provided for all new bridges. The abutment slope protection for road overbridges is at least over the area directly beneath the superstructure and sufficient of the sides for the embankment to prevent erosion and undermining.

(4) The abutment protection of a widened bridge is similar in style to the existing bridge.

(5) Where reinforced soil system walls are used as the front face of the abutment, the design includes a primary support system for the abutment headstock with a design life of at least 100 years.

Table 8.2.22.2.A—Heavy load platform position for road bridges

In 2 marked lanes with the vehicle travelling ± 1m either side of centre of any 2 adjacent marked lanes. Consideration should be given to the most likely path of the vehicle. The AS 5100 Set-2007 Bridge Design Set coexistent half SM1600 on the adjacent ramp is applied to create the worst effect.

One lane ramp

Positioned on a one-lane ramp so located by the designer. The tolerance on lateral position is specified.

(3) Where full width access greater than 1.8m is possible, the structure accommodates either a 6,100kg GVM full size tractor, 2,500kg utility vehicle or a mini tractor as described above.

(4) For man-made materials subject to loss of strength with increasing temperature AS 5100 Set-2007 Bridge Design Set section 17 is used to guide assessment of possible deck temperature.

8.2.22.5 Thermal loads

Bridge structures are designed for thermal effects as detailed in AS 5100 Set-2007 Bridge Design Set section 17. For determination of temperature effects, all structures are considered as coastal, taking into account the impact of climate change over the structure's design life.

8.3 Culverts

8.3.1 Design principles

(1) This section outlines the design specifications, guidelines and standards in relation to the design and construction of all new culverts.

(2) The design and construction of culvert assets aligns with the following:

(a) culvert structures are typically constructed using either box or pipe barrels, with open inlet and outlet ends so as to convey water not under pressure. Culvert asset boundaries must extend beyond the barrels to include the head walls (or parapet walls), wing walls, aprons, base slabs to support the barrels (if any), and guardrails (or handrails) structurally attached to the culvert;

(2) Where the above references are silent on any matter, a culvert is designed in compliance with one of the following technical publications:

(a) British Standards (BS 5400);

(b) American Standards (AASHTO LRFD);

(c) European Codes (Euro codes).

8.3.3 Design life

(1) A culvert and its associated structures are designed to achieve the minimum design life in Table 8.3.3.A without major maintenance or replacement of elements whilst remaining safe and functional.

(2) If part of an asset including asset items and asset sub-items is not readily accessible for maintenance or replacement, its design satisfies the design life requirements of the asset of which it forms a part.

(3) If replacing cells of extending existing culvert crossings, the new works have a design life of 100 years.

Table 8.3.3.A—Minimum-required design life

Asset

Design life

Culvert structures and roadway support structures including underpasses

8.3.4.3 Concrete durability

(2) Cover spacers and permanent fixings incorporated within the concrete covers zone are structurally adequate, durable and compatible with the material characteristics of the surrounding concrete, with good adhesion, so that their inclusion will not cause any cracking, spalling or other defect leading to corrosion of the reinforcement within the structure’s design life.

8.3.4.4 Steel durability – steel culverts

Steel pipe or arch culverts are not used for stormwater management purposes.

8.3.4.6 Miscellaneous components durability

(1) Structures are designed to enable items such as tidal flaps, debris grates, silt traps, railings and drainage connections to be readily accessible for inspection, maintenance, renewal or replacement.

(2) Structures are designed so that all corrosion protection systems, including concrete covers can be easily inspected, maintained or renewed.

8.3.5 Widening

(1) If future widening of a culvert may be required allowance is made in design for connection of the future widening connection.

(2) A connection for a future widening is designed and constructed to minimise or eliminate the need to alter the parent structure.

(3) Details of the widening methodology, including outline drawings, method of attachment and transmitted forces are allowed for in design and included on the contract general arrangement drawings.

(4) Exposed reinforcement does not project from a structure in anticipation of a future widening.

(5) The widening of any existing structures provides a construction solution that is consistent with the existing structure in terms of stiffness, fixity, continuity and appearance.

(6) The effects of the widening on the capacity of the existing structure are considered and the existing structure strengthened as required to ensure no reduction in vehicle capacity or flood immunity.

8.3.6 Barriers and rails

(1) All barriers and railings:

(a) are durable, robust, tamper proof and capable of surviving up to a 20 year ARI flood without damage and with minimal maintenance throughout their 40 year design life;

(b) when required to prevent falls from height barriers and railings are designed in addition to the normally applied load cases and combinations to sustain coexistent 20 year ARI water drag forces with the AS 5100 Set-2007 Bridge Design Set pedestrian barrier loads without damage;

(c) are designed so that in the event of failure above a 20 year ARI flood, there will be no damage to the supporting structure or base fixings to enable quick and easy repair or replacement with minimal disruption or nuisance to the public.

(2) Collapsible barriers and railings incorporating replaceable weak links (e.g. shear pins) are used if a whole-of-life cost–benefit analysis shows that it is a better value solution than a normal installation

(3) Collapsible barriers and railings are tamper proof.

(4) Collapsible barriers or railings of any type are not relied upon to mitigate flood impacts to adjoining land or infrastructure.

8.3.7 Public utilities

(1) A culvert is designed to accommodate present and future requirements for services crossing the structure.

8.3.8 Hydrology

8.3.8.1 General

(1) The hydraulic design of culverts must not result in adverse impacts, such as increase in water levels or flow velocities, and significant change of flood patterns. Design minimises the impacts on the waterway environment.

(2) Regard is given to catchment management plans or stormwater management plans for the watercourse.

(3) All culverts are designed to ensure that the total waterway (including culvert) can pass flows up to the 100 year ARI flood without significant damage to the road embankments and/or culvert structure.

(4) Consideration is given to the need to assess the 2,000 year ARI flood for an ultimate limit state where multi-cell culverts are being proposed along arterial transport routes.

(5) The hydraulic loads on major culverts and retaining walls is based on a 2000 year ARIflood and probable maximum flood for ultimate-limit state flood levels and flows and a 20 year ARI flood for serviceability-limit state flood levels and flows.

(6) Stability of road embankments is designed according to a 100 year ARI flood.

(7) The impact of climate change during the structure’s life is assessed and taken into account in assessing flood levels and velocities.

8.3.8.2 General hydraulic standards

Modelling to assess the flood impact of crossings for various pavement heights above the invert of a waterway uses the following standards:

(a) height of pavement above invert less than 500mm – a handrail or barrier may not be required, although a ‘lip’ not exceeding 150mm high to act as a bump stop for wheelchairs (etc.) may be required. If the handrail or barrier can be avoided, no representation of blockage is required in the hydraulic model, other than the deck and supporting piers;

(b) height of pavement above invert between 500mm and 1,000mm – a standard tubular hand and mid-rail barrier without infill is generally required. This is represented by 50% blockage in the hydraulic model;

(c) height of pavement above invert greater than 1,000mm – a balustrade barrier is generally required. This is represented by 100% blockage in the hydraulic model;

(d) unless otherwise advised by the Registered Professional Engineer Queensland civil/structural designer, handrail height above the pavement height shall be taken as 1,100mm for pedestrian crossings and 1,400mm for bikeways or shared paths.

8.3.8.3 Particular hydraulic standards

(1) Crossings are designed to have no adverse impacts on flooding and flood patterns.

(2) If afflux or debris build up associated with a barrier or railing is an issue, a no handrail crossing may be considered by the designer if the height of pavement above invert is 1m or less and the pavement of the crossing is widened accordingly, provided the design is supported by a risk management assessment report and includes:

(a) a minimum 1.5m-wide concrete shoulder on either side of path to taper back to standard path width after extent of crossing;

(b) a red coloured shoulder with a 100mm-wide painted yellow line along its internal edge;

(c) flexible road edge guide posts at 2m (minimum) spacing installed along each side of the crossing;

(2) Loading applied to culverts includes dead load, vertical and horizontal soil pressure, traffic loads for culverts under roadways, bikeways and pedestrian paths, and internal water pressure. Handling and transporting loads is also considered for pre-cast culverts.

(3) Pipe culverts are designed for a range of fills from zero to the maximum design height.

(7) A culvert supporting road traffic is designed for SM1600 and heavy load platform (HLP320 and LHP400) traffic loads in compliance with AS 5100 Set-2007 Bridge Design Set.

(8) The position for a heavy load platform complies with Table 8.3.9.A.

(9) If roadways over culverts are widened and the culverts are extended, the design loading of the extended culvert units complies with the SM1600 loading and the heavy load platform loading of AS 5100 Set-2007 Bridge Design Set, except as specified in Table 8.3.9.B.

Table 8.3.9.A—Heavy load platform position for roadways over culverts

In 2 marked lanes with the vehicle travelling ± 1m either side of centre of any 2 adjacent marked lanes. Consideration should be given to the most likely path of the vehicle. The AS 5100 Set-2007 Bridge Design Set coexistent half SM1600 on the adjacent ramp is applied to create the worst effect.

One-lane ramp

Positioned on a one-lane ramp so located by the designer. The tolerance on lateral position is specified.

Table 8.3.9.B—Vehicle loads for widening roadways over culverts

Roadways widening type

Clarification of heavy load platform position

Widening < 1 lane in width

The existing culvert design load is adopted for all lanes.

Widening > 1 lane but fewer than 2 lanes

The widening is designed for the SM1600 load and the heavy load platform loading used for the existing culvert design.

8.4 Tunnels

8.4.1 Design principles

(1) This section outlines the design specifications, guidelines and standards in relation to the design and construction of tunnels.

(2) The design and construction of tunnels aligns with the following:

(a) structural design is based on proven methods, materials and technology;

(b) all structures present smooth, clean lines with minimum structural depth consistent with their spans and method of construction.

(2) Where the above references are silent in relation to specific standards or technical requirements, compliance is with one of the following technical publications:

(a) British Standards BS 5400;

(b) American Standards (AASHTO LRFD);

(c) European Codes (Euro codes);

(d) Department of Transport and Main Roads Bridge Design Criteria.

8.4.3 Design life

(1) All tunnels and associated structures are designed and constructed to achieve the minimum design life in Table 8.4.3.A without major maintenance or replacement of elements whilst remaining safe and functional.

(2) If part of an asset including asset items and asset sub-items is not readily accessible for maintenance or replacement, it satisfies the design life requirements of the asset which it forms a part.

(3) A replacement methodology is specified for components that have a life shorter than the structure design life.

Table 8.4.3.A— Minimum required design life

Asset

Design life

Tunnel structures including linings and waterproofing/sealing

100 years

Bridge structures and roadway support structures including underpasses

Signage support structures, roadside barriers and other roadside furniture

40 years

Tolling system structures, gantries and other equipment structures

40 years

Mechanical equipment including ventilation plant, water treatment and fire protection systems and associated infrastructure including support systems accessible for inspection, maintenance, renewal and replacement.

8.4.4.3 Concrete durability

(2) Cover spacers or permanent fixings incorporated within the concrete covers zone are structurally adequate, durable and compatible with the material characteristics of the surrounding concrete with good adhesion, so that their inclusion will not cause any cracking, spalling or other defect leading to corrosion of the reinforcement within the structure’s design life.

8.4.4.5 Miscellaneous components durability

(1) Tunnels are designed to enable items such as lighting, ventilation and fire protection systems, plant and equipment, bearings, expansion joint seals, railing and drains to be readily accessible for inspection, maintenance, renewal or replacement.

(2) Tunnels are designed so that all corrosion protection systems including concrete covers can be easily inspected, maintained or renewed.

8.4.5 Minimum clearances

Minimum vertical clearances for tunnels are compliant with Table 8.4.5.A.

Table 8.4.5.A—Minimum vertical clearances

Location

Minimum clearance

Tunnels – general

Structures carrying Council road infrastructure

5.5m

Structures carrying Council shared use paths and footpaths

3m

Emergency egress openings, passages and stairs

2.4m

(1) Lateral clearances are sufficient to ensure vehicles operating legally and allowing for dynamic sway in compliance with the Department of Transport and Main Road’s 'Road Planning and Design Manual' requirements do not damage adjacent or overhead tunnel structures, utilities, mechanical or electrical plant or equipment.

(2) Pedestrian service and emergency access passages and stairs are not less than 1.5m clear width.

(3) Openings into pedestrian service and emergency access passages and stairs are not less than 1m clear width.

(4) Public shared use paths and footpaths are not less than 3m clear width.

8.4.7 Public utilities

A tunnel is designed to accommodate present and future requirements for services running through the structure.

8.4.8 Hydrology

(1) Climate change is taken into account when assessing flood impacts.

(2) Structures are designed to prevent or minimise increased flooding or flood pattern change.

8.4.9 Flood immunity

(1) Drainage and flood control systems are designed, constructed, operated, maintained and renewed to ensure the tunnel and associated assets are protected against flooding.

(2) The tunnel and associated assets are designed so that the connection ramps and tunnels are protected by non-mechanical fixed means from external catchment run-off under a minimum 10,000 year ARI flood.

8.4.10 Drainage

Tunnel drainage systems:

(a) are of sufficient capacity to maintain all traffic lanes flood free in both directions for stormwater run-off from portal areas for the design 100 year ARI flood;

(e) have facilities necessary to identify, isolate, treat and safely dispose of contaminated run-off and water arising from road traffic incident, groundwater, maintenance, fire fighting and other water ingress events without harm or nuisance;

(g) all sumps that are to discharge to holding tanks are to be suitably lined, sealed and vented to atmosphere with minimum duty and 2 standby pumps;

(h) all sumps and equipment are designed and constructed for easy inspection, maintenance, operation and renewal and incorporate automatically controlled, with manual back up duty, and standby forced ventilation systems;

(i) all pumps are easy and safe to install operate, maintain, renew and replace;

(j) all pumps are equipped with flood-resistant monitoring, alarm systems and remote automatic and manual control systems.

8.4.11 Groundwater impacts

(1) Tunnels do not cause nuisance, damage or environmental harm as a result of changes in groundwater levels and flows associated with their design, construction, operation, maintenance, renewal or retirement.

(2) Tunnels requiring permanent dewatering are not provided.

(3) Tunnels have dry exposed faces or linings without structural or other damage, mould or chemical staining as a result of seepage or damp.

(4) All seepage is able to be collected and discharged without causing harm or nuisance to tunnel users, inspectors and maintenance personnel.

(5) Drained tunnels are designed and constructed so that:

(a) gross total seepage does not exceed 8L/s;

(b) average seepage rate per 100m tunnel length does not exceed 0.25L/s;

(c) there is no seepage through the pavement, floors and work platforms.

(6) Undrained tunnels are designed and constructed so that:

(a) gross seepage does not exceed 0.2L/m2 of tunnel circumference per day;

(b) gross seepage does not exceed 0.4L per 10m length of tunnel per day;

(c) there is no discernible water flow through the tunnel lining;

(d) there is no seepage through the pavement, floors and work platforms.

(2) A suitably qualified and experienced Registered Professional Engineer Queensland fire safety engineer is engaged prior to start of site works to provide a fire resistance and fire rating assessment report that includes:

(a) a risk-based assessment of the fire resistance requirements for all tunnel structures in compliance with AS 4825-2011 Tunnel fire safety and Queensland Fire and Rescue Service requirements and guidelines;

(b) detailed drawings identifying and referencing all load bearing and fire separation elements including smoke ducts and ventilation equipment critical to the asset performing as required in a fire event to ensure public, tunnel workers and emergency services personnel safety;

(c) a schedule of the fire resistance or fire rating to be achieved for each element during construction, operation, maintenance, renewal and replacement;

(d) details of the materials used including inspection frequency, life-to-first maintenance and maintenance, renewal and replacement need to perform as required throughout the tunnel's life.

(3) Where the above references are silent in relation to specific standards or technical requirements, compliance is with one of the following technical publications:

(a) British Standards (BS 5400);

(b) American Standards (AASHTO LRFD);

(c) European Codes (Euro codes).

8.5.4 Design life

(1) All earth-retaining structures are designed to achieve the minimum design life in Table 8.5.4.A without major maintenance or replacement of elements whilst remaining safe and functional.

(2) If part of an asset including asset items and asset sub-items is not readily accessible for maintenance or replacement, it satisfies the design life requirements of the asset of which it forms a part.

(3) A replacement methodology is specified for components that have a life shorter than the structure design life.

8.5.5.2 Concrete durability

(2) Cover spacers or permanent fixings incorporated within the concrete covers zone are structurally adequate, durable and compatible with the material characteristics of the surrounding concrete with good adhesion, so that their inclusion will not cause any cracking, spalling or other defect leading to corrosion of the reinforcement within the structure’s design life.

8.5.5.4 Timber durability

8.5.5.5 Miscellaneous components durability

(1) Structures are designed to enable items such as expansion joint seals, railing and drains to be readily accessible for inspection, maintenance, renewal or replacement.

(2) Structures are designed so that all corrosion protection systems including concrete covers can be easily inspected, maintained or renewed.

8.5.6 Minimum clearances

Minimum clearances for retaining walls are compliant with Table 8.5.6.A.

Table 8.5.6.A— Minimum clearances

Location

Minimum horizontal clearance

Exposed faces and structure to all other assets

0.6m

Exposed face to all other assets longer than 2m

2m or ½ retained height if greater

Structure (including drainage) to property or easement boundary

2m or ½ retained height if greater

8.5.7 Ground anchors

(1) All ground anchors are removed unless there is no other reasonable technique enabling the project to proceed.

(2) If ground anchors cannot be avoided or removed they are located within the zone indicated in Figure 8.5.6.a.

(3) All temporary ground anchors are distressed and removed.

(4) Approval in writing is required from the adjoining property owners (including Council where adjoining Council land) for proposed ground anchor systems (permanent or temporary) which extend beyond the applicant’s legal property boundaries prior to installation.

8.5.8 Barriers

Where fall from height, pedestrian, bikeway or vehicle barriers are required they, their fixings and supporting structure are:

(a) designed to accord with all relevant Australian Standards;

(b) safe, durable, robust and tamper proof.

8.5.9 Public utilities

An earth-retaining structure is designed to accommodate present and future requirements for services that run through or close to the structure.

8.5.10 Hydrology

(1) The impact of climate change on earth-retaining walls, during the structure’s life, is assessed and taken into account in assessing flood levels and velocities, where liable to inundation and they are:

(b) designed to survive all water and debris forces in compliance with AS 5100 Set-2007 Bridge Design Set arising from a 100 year ARI flood with a low risk of total structural failure, third party harm or injury;

(c) designed to minimise scour potential;

(d) take into account any remaining scour potential and appropriate protection provided to ensure the new asset is not undermined or cause harm to pre-existing structures or the natural environment.

(2) Structures are designed to achieve zero afflux and no significant change to flood patterns.

8.5.11 Bituminous waterproof membrane

Water ingress or penetration will not cause accelerated degradation of the asset’s structure or unsightly staining/mould growth.

(2) An elevated structure is designed by a Registered Professional Engineer in Queensland.

8.6.3 Design life

(1) All elevated structures and elements are designed to achieve the minimum design life in Table 8.6.3.A without major maintenance or replacement of elements whilst remaining safe and functional.

(2) If part of an asset including asset items and asset sub-items is not readily accessible for maintenance or replacement, it satisfies the design life requirements of the asset of which it forms a part.

(3) A replacement methodology is specified for components that have a life shorter than the structure design life.

8.6.4.2 Concrete durability

(2) Cover spacers or permanent fixings incorporated within the concrete covers zone are structurally adequate, durable and compatible with the material characteristics of the surrounding concrete with good adhesion, so that their inclusion will not cause any cracking, spalling or other defect leading to corrosion of the reinforcement within the structure’s design life.

(14) Bolts for timber joists etc. to structural steel or timber joist to timber bearer etc. are minimum M12-316 stainless steel threaded rod with Glenlock nut and washer one end and normal nut, lock nut and washer the other.

(15) The top of timber joists and other horizontal interfaces are coated with CN emulsion and a Malthoid damp proof course laid and coated with CN emulsion to counter the effects of water held at the joist-deck interface by capillary forces.

(16) Timber is selected from the following species: spotted gum; tallowwood or ironbark.

8.6.7 Joints

Expansion joints are minimised or ideally avoided in the design. All joints are detailed to ensure that the underlying structure is not damaged by damp or water ingress.

8.6.8 Deck drainage

(1) Where there is a risk of contamination, decks must not discharge directly into watercourses or onto underlying shared paths or footpaths.

(2) All structures are designed to ensure water does not pond.

8.6.9 Barriers

8.6.9.1 General

(1) Where a structure is over permanent water deeper than 0.3m or where the drop height exceeds 1.2m, vertical balustrade pedestrian handrails with appropriate bicycle offset rail or equivalent are provided on the structures outer edge.

(c) designed so that in the event of failure above a 20 year ARI flood, there will be no damage to the supporting structure or base fixings to enable quick and easy repair or replacement with minimal disruption or nuisance to the public.

8.6.9.3 Collapsible barriers

(1) Collapsible barriers or railings incorporating replaceable weak links (e.g. shear pins) will only be considered when tamper proof and a whole-of-life cost–benefit analysis shows that it is a better value solution than a normal installation.

(2) Collapsible barriers or railings of any type are not relied upon to achieve zero afflux or to mitigate flood impacts to adjoining land or infrastructure.

8.6.10 Public utilities

An elevated structure is designed to accommodate present and future requirements for services crossing the structure.

8.6.11 Hydrology

(1) Elevated structures are designed to survive all water and debris forces in compliance with AS 5100 Set-2007 Bridge Design Set arising from a 20 year ARI flood without structural damage.

(2) Elevated structures are designed to survive all water and debris forces in compliance with AS 5100 Set-2007 Bridge Design Set arising from a 100 year ARI flood with a low risk of total structural failure, third party harm or injury.

(3) The impact of climate change during the structure’s life must be assessed and taken into account in assessing flood levels and velocities.

(4) Structures are designed to prevent or minimise increased flooding or flood pattern change.

8.6.12 Bituminous waterproof membrane

Water ingress or penetration will not cause accelerated degradation of the asset’s structure or unsightly staining/mould growth.

8.6.14 Post-tensioned concrete superstructure

(1) The superstructure does not use external pre-stressing.

(2) Where match cast joints in post-tensioned concrete are used, all match cast joints are epoxy coated, waterproofed, and have a minimum compressive stress of 2MPa under all serviceability limit state load combinations.

(2) If design requirements are not addressed in the listed standards, the design is to conform to other international codes of practice and design guidelines.

8.7.3 Design life

(1) All waterway access structures are designed to achieve the minimum design life in Table 8.7.3.A without major maintenance or replacement of elements whilst remaining safe and functional.

(2) If part of an asset, including asset items and asset sub-items, is not readily accessible for maintenance or replacement, it satisfies the design life requirements of the asset of which it forms a part.

(3) A replacement methodology is specified for components that have a life shorter than the structure design life.

Drainage elements that are accessible for refurbishment and maintenance

40 years

Signage support structures, barriers and other furniture

40 years

Floating pontoons and pile guides

25 years

8.7.4 Durability

8.7.4.1 General

A waterway access structure and its associated works meet the following minimum requirements for durability.

8.7.4.2 Concrete durability

(1) Minimum concrete strengths and associated nominated concrete covers thickness is to comply with the relevant Australian Standard.

(2) Any cover spacers or permanent fixings to be incorporated within the concrete covers zone are structurally adequate, durable and compatible with the material characteristics of the surrounding concrete with good adhesion, so that their inclusion will not cause any cracking, spalling or other defect leading to corrosion of the reinforcement within the structure’s design life.

(c) minimise scour potential and incorporate appropriate scour protection to ensure the asset, pre-existing structures or the natural environment is not significantly undermined, damaged or structurally compromised as a result of a 100 year ARI flood.

8.7.8.3 Floating structures

(b) survive 100 year flood water and debris forces in compliance with AS 5100 Set-2007 Bridge Design Set with negligible risk of any part of the structure breaking loose or floating clear and causing harm;

(c) minimise scour potential and incorporate appropriate scour protection to ensure the asset, pre-existing structures or the natural environment is not significantly undermined, damaged or structurally compromised as a result of a 100 year ARI flood.

8.7.9 Waterproofing

The designer ensures that water ingress, pressure or penetration will not cause accelerated degradation of the asset’s structure or unsightly staining/mould growth.

8.7.10 Material standards and specifications

Materials fit for purpose in the aggressive marine environment complying with relevant Australian Standards are used.

8.7.12 Structural inspections

All new, rehabilitated or extended structures have a Level 2 inspection at practical completion (On Maintenance) and end of the defects liability period (off maintenance) by a qualified inspector and the report issued electronically to Council for their records.

8.8 Sea- and river wall structures

8.8.1 Design principles

(1) Section 8.8 outlines the design specifications, guidelines and standards in relation to the design and construction of sea- and river wall structures intended to be owned or maintained by Council.

(3) Section 8.8 does not apply to other free standing earth retaining structures not liable to inundation causing scour.

(4) The design and construction of sea- and river wall structures aligns with the following:

(a) structural design is based on proven methods, materials and technology;

(b) all structures have an attractive appearance appropriate to their general surroundings and any adjacent structures;

(c) sea- and river walls must use simple, straight or large radius curved alignments sympathetic to foot or shared path alignment and interfaces with adjoining development, pathways, structures and environmental features;

(d) sea- and river walls to conform to a consistent modular pattern, with emphasised vertical joints;

(e) fixings for retaining structures are concealed or integrated as a design feature;

(f) unless a feature of the architectural design, all structures are of uniform colour and surface finish, even after repair.

8.8.2 Design specifications and guidelines

(1) All sea- and river wall structures are designed to accord with the following:

(2) Where the above references are silent in respect of a particular design aspect, the design is to conform to other international codes of practice and design guidelines.

8.8.3 Design life

(1) All sea- and river walls are designed to achieve the minimum design life in Table 8.8.3.A without major maintenance or replacement of elements whilst remaining save and functional.

(2) If part of an asset including asset items and asset sub-items is not readily accessible for maintenance or replacement, it satisfies the design life requirements of the asset of which it forms a part.

(3) A replacement methodology is specified for components that have a life shorter than the structure design life.

8.8.4.2 Concrete durability

(2) Any cover spacers or permanent fixings incorporated within the concrete cover zone must be structurally adequate, durable and compatible with the material characteristics of the surrounding concrete with good adhesion, so that their inclusion will not cause any cracking, spalling or other defect leading to corrosion of the reinforcement within the structure’s design life.

(b) protected by a high-grade protective coating having a minimum maintenance-free life of 25 years. At the end of that maintenance-free life, the coating must remain soundly adhered to the metal substrate and are suitable for overcoating without removal. The re-coating must have a minimum maintenance-free life of 25 years;

(d) incorporate appropriate scour protection to ensure the asset, pre-existing structures or the natural environment is not significantly undermined, damaged or structurally compromised as a result of a 100 year ARI flood.

(2) The impact of climate change during the structure’s life is assessed and taken into account in assessing tide height, flood levels and velocities.

(3) Structures are designed to prevent or minimise increased flooding or flood pattern change.

(4) A structure is protected from accelerated degradation of the asset’s structure or unsightly staining or mould growth from water ingress, pressure or penetration by use of a bituminous membrane.

8.8.9 Material standards and specifications

Materials complying with the Department of Transport and Main Roads specifications must be used.

(5) Where required, a log barrier fence including a lock rail for access is provided in compliance with BSD-5207.

(6) The construction standards of a typical 2m high timber acoustic fence are shown in BSD-7021 and BSD-7022. These drawings do not represent suitable noise attenuation for all developments. Site specific attenuation solution for each development should be determined in accordance with the attenuation criteria and methodologies set out in the Noise impact assessment planning scheme policy.

(7) Fencing does not hinder general maintenance. Fencing incorporates vehicular access gates, or fencing panels are designed for easy removal to allow vehicular access.

(8) Pedestrian gates are incorporated in fences on road frontages.

(9) A concrete (extruded or cast in situ) mowing strip is provided under a timber fence or wall or a galvanised steel fence (including an acoustic barrier) where the fence interfaces with lawn and landscaped areas.

(10) A concrete mowing strip is a minimum of 140mm wide x 100mm deep, and is flush with the surrounding ground.

(11) A mowing strip is not required under masonry or concrete fences if the footings provide access for mowing.

(12) Under the Neighbourhood Disputes Resolution Act 2011, Council is required to share the cost of a dividing fence where the Council has freehold ownership of the adjoining property. Council is not liable for costs where the land it controls is crown land held in trust (e.g. parkland or roads) nor is Council responsible for sharing fencing costs at easements that are granted in favour of Council inside private properties.

(14) It is preferred that fencing is not erected inside a drainage easement, overland flow path, flood regulation line or waterway corridor.

(15) Fences that inhibit the conveyance of floodwaters (e.g. debris retaining, solid fences) are not preferred.

(16) If solid fences are used between private lots where the overland flow is shallow (generally less than 200mm deep), solid fences can be constructed provided that openings are installed at ground level to accommodate overland flows.

(18) Open post and rail is where no panels of fencing are incorporated between the post and rail structure to provide minimum resistance to flood flows (e.g. log barrier fencing, galvanised tubular handrail).

(19) Collapsible fencing is where sections of the fence are designed to collapse under flood loading so as not to increase flood levels, but are also anchored to avoid being washed away.

(20) Collapsible fencing has low strength ties holding it in place during non-flood times.

(21) Swing fencing is where sections of the fence are designed to yield under the pressure of flood flows so as not to increase flood levels, but are also anchored to avoid being washed away.

(22) Panels in swing fencing are fitted with hinges or pivot points to allow opening during floods.

(23) Swing fencing has low strength ties holding it in place during non-flood times.

(24) Lifting fencing is where sections of the fence may be temporarily raised to not obstruct flood flows.